An apparatus of this kind is described and illustrated in DE-OS 37 19 148. In this known embodiment the components are conveyed to and from the testing station by transporting means, and while being conveyed the components are accommodated in holders attached exchangeably to the transporting means.
The transporting means comprises an endless flat belt which runs in a horizontal plane about two wheels rotatable in a horizontal plane and carries the holders by which the components are transported from the loading station to the testing station and from there to the unloading station spaced uniformly from one another on its vertical outer surface The holders each have a vertical shaft into which at the loading station the associated component slides under gravity from a bar magazine arranged above it. At the unloading station the lower end of the shaft is opened so that the tested component can slide down into a guide passage, likewise under gravity, which leads to a bar magazine. Since the components are of different shapes and sizes, a corresponding number of types of holder with component-specific shaft forms are needed to receive them. If necessary holders of one type attached to the transporting means are exchanged for holders of another type.
The functional efficiency of the known apparatus suffers from the fact that loading the transporting means with the components is associated with a risk of damaging the components. This danger arises both when feeding the components into the bar magazine and when loading the transporting means with the components, when the first component must always be moved forwards while at the same time the second component must be held back. This is effected by separating devices and/or arresting devices for the components. The danger of causing damage naturally also exists in a similar way when unloading the components. It must be taken into consideration that electronic components are delicate prefabricated parts such that every active mechanical contact involves the risk of damage. In the case of IC's there is a danger of bending the small and delicate connection contacts. It must also be taken into consideration that electronic components such as IC's are difficult to handle when loading and unloading because of their complicated structure.
It is known from DE-OS 36 38 430 to grasp IC's by means of a movable gripper and convey them to a tester. Even with this arrangement damage to the IC's cannot be excluded.